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/*
* Copyright (C) 2017-2019 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <wtf/Assertions.h>
#include <wtf/HashTraits.h>
#include <wtf/UniqueArray.h>
namespace WTF {
class StackShot {
WTF_MAKE_FAST_ALLOCATED;
public:
StackShot() { }
ALWAYS_INLINE StackShot(size_t size)
: m_size(size)
{
if (size) {
m_array = makeUniqueArray<void*>(size);
int intSize = size;
WTFGetBacktrace(m_array.get(), &intSize);
RELEASE_ASSERT(static_cast<size_t>(intSize) <= size);
m_size = intSize;
if (!m_size)
m_array = nullptr;
}
}
StackShot(WTF::HashTableDeletedValueType)
: m_array(deletedValueArray())
, m_size(0)
{
}
StackShot& operator=(const StackShot& other)
{
auto newArray = makeUniqueArray<void*>(other.m_size);
for (size_t i = other.m_size; i--;)
newArray[i] = other.m_array[i];
m_size = other.m_size;
m_array = WTFMove(newArray);
return *this;
}
StackShot(const StackShot& other)
{
*this = other;
}
void** array() const LIFETIME_BOUND { return m_array.get(); }
size_t size() const { return m_size; }
std::span<void*> span() const LIFETIME_BOUND { return unsafeMakeSpan(m_array.get(), m_size); }
explicit operator bool() const { return !!m_array; }
bool operator==(const StackShot& other) const
{
if (m_size != other.m_size)
return false;
for (size_t i = m_size; i--;) {
if (m_array[i] != other.m_array[i])
return false;
}
return true;
}
unsigned hash() const
{
unsigned result = m_size;
for (size_t i = m_size; i--;)
result ^= PtrHash<void*>::hash(m_array[i]);
return result;
}
bool isHashTableDeletedValue() const
{
return !m_size && m_array.get() == deletedValueArray();
}
// Make Spectrum<> happy.
bool operator>(const StackShot&) const { return false; }
private:
static void** deletedValueArray() { return std::bit_cast<void**>(static_cast<uintptr_t>(1)); }
UniqueArray<void*> m_array;
size_t m_size { 0 };
};
struct StackShotHash {
static unsigned hash(const StackShot& shot) { return shot.hash(); }
static bool equal(const StackShot& a, const StackShot& b) { return a == b; }
static constexpr bool safeToCompareToEmptyOrDeleted = false;
};
template<typename T> struct DefaultHash;
template<> struct DefaultHash<StackShot> : StackShotHash { };
template<> struct HashTraits<StackShot> : SimpleClassHashTraits<StackShot> { };
} // namespace WTF
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